The complete stopping of bleeding during operation and postoperation is considerably difficult in the prostatectomy. Benign prostatic hyperplasia (abbreviation: BPH) is not infrequent among older males. More careful attention is needed during operation and/or rehabilitation as than with young patients because of the poor risk. It was very important that to control the bleeding during operation and after operation, and to shorten the period for complete wound healing.In the present paper, 53 cases are reported who suffered from BPH and received retropubic prostatectomy in our Department in the period of 3 years from 1970 through 1972. Trans aminomethyl-cyclohexane-carboxylic acid (abbreviation: t-AMCHA) was the only coagulant used by intravenous injection during and after operation. The relationships of total doses of t-AMCHA used to the duration of gross hematuria during and after operation and the time to complete wound healing were studied. The results were as follows.It was found that the duration of hematuria was shortest at total doses ranging from 41g to 50g. The mean value was 8.6 days. The time to complete healing shorter at total t-AMCHA doses of 51-60g. The mean value was 8.5 days. We believe that the suitable total doses of t-AMCHA for retropublic prostatectomy is from 41g to 60g.